The Barents and Chukchi Seas: Comparison of two Arctic shelf ecosystems

• Main Authors: Hunt, George L, Blanchard, Arny L, Boveng, Peter, Dalpadado, Padmini, Drinkwater, Kenneth F, Eisner, Lisa, Hopcroft, Russ R, Kovacs, Kit M, Norcross, Brenda L, Renaud, Paul, Reigstad, Marit, Renner, Martin, Skjoldal, Hein Rune, Whitehouse, Andy, Woodgate, Rebecca A
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: eScholarship, University of California 2013
• Subjects: Climate Action; Oceanography; Arctic; Barents Sea; Norwegian Sea; Bering Sea; Chukchi Sea; Chukchi; Zooplankton
• Online Access: https://escholarship.org/uc/item/4sc572cp

This paper compares and contrasts the ecosystems of the Barents and Chukchi Seas. Despite their similarity in a number of features, the Barents Sea supports a vast biomass of commercially important fish, but the Chukchi does not. Here we examine a number of aspects of these two seas to ascertain how they are similar and how they differ. We then indentify processes and mechanisms that may be responsible for their similarities and differences.Both the Barents and Chukchi Seas are high latitude, seasonally ice covered, Arctic shelf-seas. Both have strongly advective regimes, and receive water from the south. Water entering the Barents comes from the deep, ice-free and "warm" Norwegian Sea, and contains not only heat, but also a rich supply of zooplankton that supports larval fish in spring. In contrast, Bering Sea water entering the Chukchi in spring and early summer is cold. In spring, this Bering Sea water is depleted of large, lipid-rich zooplankton, thus likely resulting in a relatively low availability of zooplankton for fish. Although primary production on average is similar in the two seas, fish biomass density is an order of magnitude greater in the Barents than in the Chukchi Sea. The Barents Sea supports immense fisheries, whereas the Chukchi Sea does not. The density of cetaceans in the Barents Sea is about double that in the Chukchi Sea, as is the density of nesting seabirds, whereas, the density of pinnipeds in the Chukchi is about double that in the Barents Sea. In the Chukchi Sea, export of carbon to the benthos and benthic biomass may be greater. We hypothesize that the difference in fish abundance in the two seas is driven by differences in the heat and plankton advected into them, and the amount of primary production consumed in the upper water column. However, we suggest that the critical difference between the Chukchi and Barents Seas is the pre-cooled water entering the Chukchi Sea from the south. This cold water, and the winter mixing of the Chukchi Sea as it becomes ice covered, result in ...